Well hello there,

So I just had a Svbony SV305M Pro camera delivered. Tried it for a few hours last night. A few questions resulted from this.

I am using a Raspberry Pi 4 8 GB running Astroberry, and specifically the Kstars/Ekos software. My new camera worked pretty well for guiding using the internal guider module of Ekos, although, every now and then, a frame would appear different fro mthe rest. Instead of the regular gray and somewhat grainy pictures speckled with Stars, these deviants would have a pitch black background with a few of the stars visible and also being sharply white. So, some kind of super high contrast deal. Why might this be? The auto stretch messing up? The drivers and camera actually handing over pictures actually looking like this?

Also, I had the camera connected via USB 2. Is there any benefit to using USB 3? For instance, not having the situation with the sometimes weird images?

Regards

Hello Simon,

I use the SV305M as my main imager since 3 month (with a T7C as guider), and didn't encounter this issue.
I use a RPi4, like you, with stellarmate OS.

Is your camera plugged strait on the RPi ?

I use a 12v USB hub, so, the camera is powered by the hub. Couldn't it be a power stability issue ?

USB3 is useful for planetary imaging (up to 110 fps on my laptop). But for guiding, or long exposure, USB2 fills the needs.

Best regards !

Thx8411

Hi Colin,

Oh, I got the sv305M to replace my T7C. The T7C gave me even freakier images where sections of the images switched places. This left Ekos very confused, as far as it was concerned it seemed like some of the stars were jumping around in the night sky. Should I benoticing a pattern here... Cameras owned by me perform strangely??

I have a power delivery box and dew heater controller called Astrolink 4 Pi, this is also housing the Raspberry Pi. So, connected directly into the Pi is my EQ6-R and my imaging camera ZWO 533MC Pro. Connected into the USB hub of the 533MC is my Sesto Senso 2 Focuser. I have heard that this might be a powered USB hub? Anyhow, last session I had the SV305M connected directly into of the USB 2 ports of the Pi and tonight I will with the camera connected into the USB hub of my 533MC.

Bandwidth-wise, I know that USB 2 is plenty for the application of guding. I was wondering if there might be any other advantages to USB 3 like stability of power, connection or anything like that.

I also noticed while preparing for tonights session, that when I built a dark library for the SV503, some of the images seemed way cleaner than the rest. Instead of looking like mostly noise and the odd streaks and patterns, the clean images had a more pure gray bakground with a few white dots. The difference between the images noticed here seemed very similar to what I experienced when guiding the other day.

Here follows two images meant to illustrate what I have been talking about.

Messed up-

Correct?-

Hello Simon,

What are you gain settings ?

Did you try to capture a long sequence of 3s images, to compare it ?
What length your USB cables are ? Did you try to switch the USB cables ?

Best regards,

Thx8411

Hi Simon

I have an SV305 attached to a sv106 guide scope (60mm aperture 240 fl) and am using astroberry, however when I set the guiding up I see quite tiny dots for the stars (there seems to be a certain amount of hit and miss with being able to zoom in with different parts of ekos). Are you sure you are focused ok?

Guiding with the sv305 and ekos using the default multi star setup seems to have worked pretty much out of the box (trying hard here to forget the annoying crashes and lockups I’ve had). I’ve used 1 and 3 sec exposures with/without darks with a gain of 300, 12 bit mode stretched to 16bit. I see noise but it seems to pick out the stars even with clouds drifting across.

Regards

Nigel

PS I’m a total beginner

Mount : iexos-100
Guide : sv106 -60mm/240fl
Guide camera : sv305
Main Camera : Sony A7Rii with Sigma 100-400 zoom
Controller : Raspberry Pi with Astroberry

I am not sure what the gain was set at for the two images in my previous post. In the INDI-panel it will default to 10. I did change that to 110 at one time, but Kstars crashed at least one time during the season and the gain would then have reverted to 10. Not sure about what it was set at when I took the two screenshots. So, it was set at either 10 or 110.

Just now, that is during the daytime, I tried taking two sets of images with the cap on the scope. One set of 100 3 second exposures at 110 gain, and a second set of 100 4 second exposures, again, at gain 110. All images, except for 1 turned out OK. The 70th of the 100 4 seconds had that odd appearance. I would say that during my session a few nights ago now, the "failure rate" was slightly higher than that, but not by much.

The USB cable that I have plugged into the SVBONY camera is one of the two the 50 centimeter USB 2 cable that were included with my 553MC camera. I have not yet tried with a different USB cable. Will give the 2 meter long USB 3 cable that was bundled with the SV305M a go.

Regards,

Simon

Hello Nigel,

My guide scope is a generic, non-branded, 50/190 scope with a helical focuser. I for sure am NOT certain that I am focused correctly. Would you mind sending a picture exampling what your typical guiding image look like? Trying out the guide scope and camera today, during daylight, I did find that my focus was set in such a way that it would render sharp images of object(house and a forest) located at a distance of about 1.1 km. How this information would transfer onto to focus setting needed for imaging stars, at practically infinite distance, I do not know. But, I feel it would not be way off at least.

Do you set the gain for the camera in the INDI-panel? I have not found anywhere to set the gain inside of the guiding module of ekos. Is there a toggle for having the bit depth of the images increased to 16 bit?

I do not know whether Ekos do have trouble picking out guide stars for me. Although, I have noticed that the SNR does take a complete nosedive, straight to 0, quite often. Looking at the images in the preview window, during these stretches of time, it does look like it can still find the same stars in the images. And I have not seen any correlation between the SNR going to 0 and the occasional messed up image. Staying of the topic of SNR. What is considered a normal range of values for SNR? I have got the impression that 500 is quite high?

Regards,

Simon

So, most of the dark frames look like this:



Some of them look like this:

Hi

My darks look like the second one. Having to look at them via astap but I’ve only seen those types. As I’m using them for guiding they are only in the range 1 to 5 secs, no bin or 2x2 bin (4x4 bin seems to be all white for some reason).

My sv305 (usb 2) is using the supplied cable which has two connectors at the pi end. It’s plugged into a powered hub as I kept having power warnings in my logs.

Hi

My darks look like the second one. Having to look at them via astap but I’ve only seen those types. As I’m using them for guiding they are only in the range 1 to 5 secs, no bin or 2x2 bin (4x4 bin seems to be all white for some reason).

My sv305 (usb 2) is using the supplied cable which has two connectors at the pi end. It’s plugged into a powered hub as I kept having power warnings in my logs.

and my sv305 setup in the indi panel looks like :-

Frame format and 12 buts stretch are what I’m using to get the image to use the full 16bits. Suspect not really needed for guiding and probably is wasting bandwidth on the usb.